https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118626
Bug ID: 118626
Summary: C++20 std::variant causes a segmentation fault
Product: gcc
Version: 13.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: JanPapuch at seznam dot cz
Target Milestone: ---
This issue may be a regression of [Bug
104470](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104470).
Output of `gcc -v -save-temps --std=c++20 main.cpp`:
```
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
13.1.0-8ubuntu1~20.04.2' --with-bugurl=file:///usr/share/doc/gcc-13/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2,rust --prefix=/usr
--with-gcc-major-version-only --program-suffix=-13
--program-prefix=x86_64-linux-gnu- --
enable-shared --enable-linker-build-id --libexecdir=/usr/libexec
--without-included-gettext --enable-threads=posix --libdir=/usr/lib
--enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-vtable-verify --en
able-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.1.0 (Ubuntu 13.1.0-8ubuntu1~20.04.2)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++20' '-mtune=generic'
'-march=x86-64' '-dumpdir' 'a-'
/usr/libexec/gcc/x86_64-linux-gnu/13/cc1plus -E -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE main.cpp -mtune=generic -march=x86-64 -std=c++20
-fpch-preprocess -fasynchronous-unwind-tables -fstack-protector-strong -Wformat
-Wformat-security -fstack-clash-protection -fcf-protection -o a-main.ii
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/13"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/13/include-fixed/x86_64-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/13/include-fixed"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/13/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/13
/usr/include/x86_64-linux-gnu/c++/13
/usr/include/c++/13/backward
/usr/lib/gcc/x86_64-linux-gnu/13/include
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=c++20' '-mtune=generic'
'-march=x86-64' '-dumpdir' 'a-'
/usr/libexec/gcc/x86_64-linux-gnu/13/cc1plus -fpreprocessed a-main.ii -quiet
-dumpdir a- -dumpbase main.cpp -dumpbase-ext .cpp -mtune=generic -march=x86-64
-std=c++20 -version -fasynchronous-unwind-tables -fstack-protector-strong
-Wformat -Wformat-security -fstack-clash-protection -fcf-protection -o a-main.s
GNU C++20 (Ubuntu 13.1.0-8ubuntu1~20.04.2) version 13.1.0 (x86_64-linux-gnu)
compiled by GNU C version 13.1.0, GMP version 6.2.0, MPFR version
4.0.2, MPC version 1.1.0, isl version isl-0.22.1-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 391880e3be75f4e1ac78bddcb50fff0c
In file included from main.cpp:2:
/usr/include/c++/13/variant: In substitution of ‘template<class ... _Types>
template<class _Tp, class> using std::variant<_Types>::__accepted_type =
std::variant<_Types>::__to_type<__accepted_index<_Tp> > [with _Tp = _Tp&&;
<template-parameter-2-2> = typename std::enable_if<std::variant<Node<L, R>,
Leaf>::__not_self<_Tp&&>, void>::type; _Types = {Node<L, R>, Leaf}]’:
main.cpp:43:9: required from here
/usr/include/c++/13/variant:1383:43: internal compiler error: Segmentation
fault
1383 | using __accepted_type = __to_type<__accepted_index<_Tp>>;
| ^~~~~~~~~~~~~~~~~~~~
0xdd3543 crash_signal
../../src/gcc/toplev.cc:314
0x7f01cdb5308f ???
/build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0x84c3eb tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:20450
0x85bf30 tsubst_expr(tree_node*, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:19895
0x85ff09 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:13766
0x8601b2 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:13748
0x85037a tsubst(tree_node*, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:15966
0x85a562 tsubst_decl
../../src/gcc/cp/pt.cc:15307
0x868e73 instantiate_template(tree_node*, tree_node*, int)
../../src/gcc/cp/pt.cc:22132
0x8503fe instantiate_alias_template
../../src/gcc/cp/pt.cc:22215
0x8503fe tsubst(tree_node*, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:15967
0x870567 rewrite_tparm_list
../../src/gcc/cp/pt.cc:29761
0x870d93 alias_ctad_tweaks
../../src/gcc/cp/pt.cc:30259
0x847904 deduction_guides_for
../../src/gcc/cp/pt.cc:30494
0x847ad7 do_class_deduction
../../src/gcc/cp/pt.cc:30641
0x847ad7 do_auto_deduction(tree_node*, tree_node*, tree_node*, int,
auto_deduction_context, tree_node*, int, tree_node*)
../../src/gcc/cp/pt.cc:30841
0x88179f finish_compound_literal(tree_node*, tree_node*, int, fcl_t)
../../src/gcc/cp/semantics.cc:3213
0x7fa14c cp_parser_functional_cast
../../src/gcc/cp/parser.cc:32611
0x80b203 cp_parser_postfix_expression
../../src/gcc/cp/parser.cc:7703
0x7f382c cp_parser_binary_expression
../../src/gcc/cp/parser.cc:10147
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <file:///usr/share/doc/gcc-13/README.Bugs> for instructions.
```
